import json

testStr = '''
{
 "firstName":"John",
 "lastName" :"Smith",
 "adress":{
  "streetAddress":"21 2nd Street",
  "city":"New York",
  "state":"NY",
  "postalCode":10021
  },
 "phoneNumbers":[
  "212 555-1234",
  "646 555-4567"
  ]
}
'''

# Deserialize s (a str or unicode instance containing a JSON document) to a Python object.
obj = json.loads(testStr)

print("firstName:" + obj["firstName"])
print("city:" + obj["adress"]["city"])
print("phoneNumbers:" + str(obj["phoneNumbers"]))

# Serialize obj to a JSON formatted str.
str = json.dumps(obj,indent=2)
print(str)

the output:
firstName:John
city:New York
phoneNumbers:[u'212 555-1234', u'646 555-4567']
{
  "lastName": "Smith",
  "phoneNumbers": [
    "212 555-1234",
    "646 555-4567"
  ],
  "adress": {
    "postalCode": 10021,
    "city": "New York",
    "streetAddress": "21 2nd Street",
    "state": "NY"
  },
  "firstName": "John"
}
